Aortopulmoary electrical stimulator-pressure transducer

ABSTRACT

In an embodiment herein, an aortopulmonary stimulation device is provided including a first electrode for placement on or in the aorta, and a second electrode for placement on or in the pulmonary artery. The embodiment includes a control unit associated with the first and second electrodes for delivering electrical stimulation to the first and second electrodes, wherein the stimulation is delivered to both the first electrode and the second electrode, or to the first electrode or the second electrode to reduce afterload.

BACKGROUND

The degree of tension or stress on a heart muscle fiber as it contracts is termed the after load. Because pressure within the ventricles rises rapidly from a diastolic to a systolic value as blood is pumped out into the aorta and pulmonary arteries, the part of the ventricle that first contracts due to an excitatory stimulation pulse does so against a lower after load than does a part of the ventricle contracting later. Therefore, after load is the end load against which the heart contracts to eject blood. Many factors may influence the after load, one of which is the aortic pressure the left ventricular muscle must overcome to eject blood. A higher aortic/pulmonary pressure increases the after load on the left/right ventricle, respectively. The tension on the muscle fibers in the heart wall is the pressure within the ventricle multiplied by the volume within the ventricle divided by the wall thickness according to Laplace's law. This ratio is another factor used in determining the after load. By applying pressure on certain portions of the heart, after load can be greatly reduced or eliminated.

Prior art devices which attempt to address the aforementioned problems include pump-devices which surround certain portions of the heart to stimulate the portions. Other prior art devices include components that cross the pulmonic and tricuspid valves in order to stimulate the pulmonary artery.

Some other methods of attempting to modulate after load may include an extra-aortic balloon pump enabled to encircle the ascending aorta. This requires dissecting the aorta free from the pulmonary artery, which it abuts.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides a view of an embodiment of the placement of the device on a heart, in one example.

FIG. 2 provides a schematic of an aortopulmonary electrical stimulation embodiment.

FIG. 3 provides a non-limiting embodiment of an aortopulmonary electrical stimulation device including a sleeve array.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles and operation of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to those skilled in the art to which the invention pertains.

It is to be noted that the terms “first,” “second,” and the like as used herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The terms “a” and “an” do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. The modifier “about” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., includes the degree of error associated with measurement of the particular quantity). It is to be noted that all ranges disclosed within this specification are inclusive and are independently combinable.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise these terms do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. Furthermore, to the extent that the terms “including,” “includes,” “having,” “has,” “with,” or variants thereof are used in either the detailed description and/or the claims, such terms are intended to be inclusive in a manner similar to the term “comprising.” Moreover, unless specifically stated, any use of the terms first, second, etc., does not denote any order, quantity or importance, but rather the terms first, second, etc., are used to distinguish one element from another.

The inventor has identified a condition of ambulatory heart failure treatment is after load reduction. Issues with after load often appear in cardiac surgery procedures. In order to remedy and/or prevent issues associated with these procedures, such as after load, the inventor has identified a novel method that induces beneficial neuro endocrine changes in a subject by pressure-induced activation of aortic baroreceptors.

The inventor has discovered that by stimulating the aorta and pulmonary artery with electrodes or otherwise as described herein, the pulmonary and aortic after load may be decreased in a measurable and adjustable manner. This way the effects of the stimulation will be measureable, and any adverse effects may be avoided. Methods currently used in the art to attempt to decrease afterload include IV medications, which result in substantial side effects. For example, side effects include an increase in myocardial oxygen demand. Other medications including nitroglycerin and nitride also result in damaging side effects when used. The inventive methods described herein would eliminate the need for the very costly intravenous drips currently used perioperatively during heart surgery procedures.

To eliminate the risks of dissecting between the aorta and the pulmonary artery, the inventor has discovered that both the aorta and the pulmonary artery may be encircled through the transverse pericardial sinus, taking advantage of a natural space and eliminating any risks associated with dissecting between the aorta and pulmonary artery.

Various embodiments described herein relate to a method. Other embodiments relate to a device. According to the various electrode embodiments described, at least one electrode used and is positioned in or on the aorta. Stimulation is applied using the at least one electrode. In other electrode embodiments, at least one electrode is positioned in or on the aorta and another electrode is positioned in or on a pulmonary artery. Stimulation is applied using at least one of the electrodes. Stimulation may be applied using both electrodes, and may be applied either simultaneously or one at a time. The stimulation may be varied in strength, duration, and sequence. The stimulation may be controlled by way of a control unit as described herein.

Many of the benefits of this device are achieved by activating baroreceptors. A baroreceptor includes any sensor of pressure changes, such as sensory nerve endings in the wall of the auricles of the heart, cardiac fat pads, vena cava, aortic arch and carotid sinus, that is sensitive to stretching of the wall resulting from increased pressure from within, and that functions as the receptor of the central reflex mechanism that tends to reduce that pressure. Additionally, a baroreceptor includes afferent nerve trunks, such as the vagus, aortic and carotid nerves, leading from the sensory nerve endings. Stimulating baroreceptors inhibits sympathetic nerve activity (stimulates the parasympathetic nervous system) and reduces systemic arterial pressure by decreasing peripheral vascular resistance and cardiac contractility. Some embodiments described herein stimulate baroreceptor sites in the pulmonary artery and/or in the aorta. Consequently, in another embodiment, using electrical stimulation to activate the baroreceptors may be accomplished with or without a pump. In order to monitor the effectiveness of the baroreceptor response, transducing the pressure in the vessels would be advantageous. Consequently, in an embodiment, the inventor has discovered an aortopulmonary electrical stimulator and/or pressure transducer array to achieve the abovementioned functions. The device may be minimally invasive, in an embodiment. The device may be used with minimal incisions.

One embodiment may include a transient array including leads configured to pass through a chest wall and associate with a control unit external to the subject. The control unit may be used to activate and/or inactivate the device, as well as to control the functions and features of the device as will be described in greater detail herein. The control unit may include stimulator circuitry, which may include modules to initiate or generate electrical pulses for delivery to the electrodes. The stimulator circuitry may be a component of the microprocessor. The microprocessor may be used to vary the amplitude of the stimulation pulse, the frequency of the pulse, the burst frequency, or the duty cycle of the pulse and the wave morphology of the pulse.

In one particular, non-limiting embodiment, the array and/or the leads may be disposable. In an embodiment, the leads may be removable from the subject perioperatively. The leads described herein may be percutaneously placed, in another non-limiting embodiment. In an embodiment, proximal and distal arrays surrounding the aorta and pulmonary arteries in the transverse pericardial sinus may be used. Tape-like component may be used to insulate the components of the device from surrounding structures, in a non-limiting embodiment.

Another embodiment may include a device including an implanted control unit which may be implanted into the body of the subject connecting to the leads of the device. In one non-limiting embodiment, the control unit may be implantable in a sub-pectoral location in the subject.

Non-limiting embodiments herein include an array which may include an array of output electrodes organized such that the aorta and the pulmonary artery may be individually stimulated. The arrays may be gated to provide various levels of stimulation to the aortic and pulmonary arteries as needed.

In an embodiment, strain gauges or other measurement devices know to those skilled in the art may be used to measure aortic and pulmonary artery pressures.

In another embodiment, additional cardiac leads may be added for biventricular pacing or defibrillator. The control unit may include wired or wireless connectivity for the communication of information and data to and from the control unit. in a non-limiting example, Bluetooth wireless technology may be employed.

The terms “subject” or “patient” may be used interchangeably herein. The terms include any animal or human subject.

Various embodiments of the present subject matter relate to a lead. Various lead embodiments comprise a lead body including a first portion, and at least a first branch.

Other embodiments include a lead body including a first portion and at least a first branch and a second branch. The first portion has an end adapted to connect to an implantable medical device. The first branch may be connectable to either one of an aorta or a right or left pulmonary artery. The second branch may be connected to the first portion at a bifurcated region, in one non-limiting embodiment. The first branch may include a distal end adapted to be placed on, or fed into the aorta to securely position at least one electrode on or within the aorta. The second branch includes a distal end adapted to be placed onto or fed into a pulmonary artery to securely position at least one electrode on or within the pulmonary artery.

Various lead embodiments implement a number of designs, including an expandable stent-like electrode with a mesh surface dimensioned to abut a wall of a predetermined blood vessel, a coiled electrode(s), a fixed screw-type electrode(s), and the like. Various embodiments place the electrode(s) inside the blood vessel, into the wall of the blood vessel, or a combination of at least one electrode inside the blood vessel and at least one electrode into the wall of the blood vessel. The neural stimulation electrode(s) can be integrated into the same lead used or in another lead.

In one embodiment, a method for placing an electrode sleeve array comprising a sleeve body having a first end and a second end, and two or more electrodes, into a patient is provided. The method includes inserting a first end of a sleeve body around an aorta and pulmonary trunk through a transverse pericardial sinus, and affixing the first end of the sleeve body to a second end of the sleeve body with a fastener, such that the sleeve body encircles the aorta and the pulmonary artery.

In another embodiment, a method including positioning an aortic electrode in or near the aorta; and using the aortic electrode, to deliver stimulation to the aorta to decrease aortic after load is provided. In another non-limiting embodiment, the method may include positioning a pulmonary artery electrode in or near the pulmonary artery and using the pulmonary artery electrode to deliver stimulation to the pulmonary artery to decrease pulmonary artery after load.

In yet another embodiment, an aortopulmonary stimulation device is provided. The device includes an electrode sleeve array comprising a sleeve body, and two or more electrodes, the sleeve body comprising a first end and a second end for placement around the aorta and the pulmonary artery, wherein upon placement of the sleeve array, at least a first electrode contacts the aorta, and at least a second electrode contacts the pulmonary artery. The device includes one or more leads connecting the electrode sleeve array to a control unit, the control unit for providing electrical stimulation to the electrode sleeve array, wherein upon initiation of electrical stimulation to the electrode sleeve array, the two or more electrodes deliver differential stimulation to the aorta and/or the pulmonary artery.

Turning to the drawings, FIG. 1 provides a side view of a heart 201 including a superior vena cava 202, aorta 203 and pulmonary artery 204. A first electrode 206 may be placed in or on the aorta 203, and a first lead 207 connecting the first electrode to a control unit 210. A second electrode 208 may be placed in or on the pulmonary artery 204 and a second lead 209 connecting the second electrode 208 to the control unit 210. The control unit 210 may include a microprocessor 212 and a power source 214. The control unit 210 may be used to initiate the electrodes 206, 208 to stimulate the aorta 203 and the pulmonary artery 204. Both the aorta 203 and the pulmonary artery 204 may be simultaneously stimulated, or may be stimulated at different times. The electrodes 206, 208 may be stimulated independently of one another to differentially stimulate the aorta and pulmonary artery.

FIG. 2 provides a schematic view of the device 100, wherein a control unit 110 including a microprocessor 112, and a power source 114 is provided. A first electrode for aortic placement 116 is associated with the control unit 110, and a second electrode, for stimulation of the pulmonary artery 118 is associated with the control unit 110.

FIG. 3 provides a side view of a device embodiment 300, wherein a sleeve array 310 is placed on the aorta 312 and the pulmonary artery 314. When the sleeve array 310 is placed on the aorta 312 and the pulmonary artery 314, at least a first electrode 316 contacts the aorta 312, and at least a second electrode 318 contacts the pulmonary artery 314. Electrical simulation is delivered to the aorta 312 and the pulmonary artery 314 by way of electrical leads 320, which are connected to an electrical pulse generator, i.e., a control unit 322. A fastening device 324 may be used to affix the sleeve array 310 to the aorta 312 and pulmonary artery 314. 

What is claimed is:
 1. A method, comprising: positioning an aortic electrode in or near the aorta; and using the aortic electrode, to deliver stimulation to the aorta to decrease aortic after load.
 2. The method of claim 1, further comprising: positioning a pulmonary artery electrode in or near the pulmonary artery and using the pulmonary artery electrode to deliver stimulation to the pulmonary artery to decrease pulmonary artery after load.
 3. The method of claim 1, wherein baroreceptors are stimulated.
 4. The method of claim 1, comprising delivering a variable level of stimulation to the aorta.
 5. The method of claim 2, comprising delivering a variable level of stimulation to the pulmonary artery.
 6. The method of claim 1, further comprising one or more strain gauges configured to measure the aortic and/or pulmonary artery pressure.
 7. The method of claim 7, wherein based on the pressure detected, a variable stimulation of the aorta and/or pulmonary artery is executed.
 8. An aortopulmonary stimulation device, comprising: a first electrode for placement on or in the aorta; a second electrode for placement on or in the pulmonary artery; a control unit associated with the first and second electrodes for delivering electrical stimulation to the first and second electrodes, wherein the stimulation is delivered to both the first electrode and the second electrode, or to the first electrode or the second electrode to reduce afterload.
 9. The device of claim 8, wherein the electrical stimulation is delivered to one or more baroreceptors.
 10. An aortopulmonary stimulation device, comprising: an electrode sleeve array comprising a sleeve body, and two or more electrodes, the sleeve body comprising a first end and a second end for placement around the aorta and the pulmonary artery, wherein upon placement of the sleeve array, at least a first electrode contacts the aorta, and at least a second electrode contacts the pulmonary artery; one or more leads connecting the electrode sleeve array to a control unit, the control unit for providing electrical stimulation to the electrode sleeve array; wherein upon initiation of electrical stimulation to the electrode sleeve array, the two or more electrodes deliver differential stimulation to the aorta and/or the pulmonary artery.
 11. The device of claim 10, wherein the electrical stimulation is delivered to one or more baroreceptors.
 12. The device of claim 10, further comprising a fastener to secure the first end of the sleeve body to the second end of the sleeve body.
 13. A method for placing an electrode sleeve array comprising a sleeve body having a first end and a second end, and two or more electrodes, into a patient, comprising: inserting a first end of a sleeve body around an aorta and pulmonary trunk through a transverse pericardial sinus; affix the first end of the sleeve body to a second end of the sleeve body with a fastener, such that the sleeve body encircles the aorta and the pulmonary artery. 